The present invention pertains generally to infrared lasers and amplifiers and more particularly to stimulated Raman scattering utilized rotational transitions in a diatomic molecular gas. The present invention comprises an improvement in the inventions disclosed in copending application Ser. No. 802,400 entitled "Shifting of CO.sub.2 Laser Radiation Using Rotational Raman Resonances" filed June 1, 1977, by Norman A. Kurnit, now abandoned in favor of continuation-in-part application Ser. No. 960,409 entitled "Shifting of Infrared Radiation Using Rotational Raman Resonances in Diatomic Molecular Gases" filed Nov. 13, 1978 by Norman A. Kurnit and copending application Ser. No. 948,267 entitled "Stokes Injected Raman Waveguide Amplifier" filed Oct. 3, 1978 by Norman A. Kurnit. These commonly assigned copending applications disclose the basis for stimulated Raman scattering in a capillary waveguide and amplification of an external Stokes injection source in a Raman capillary waveguide amplifier.